B1.2

Question 1

What does Homeostasis mean?

Answer 1

Maintaining a constant internal environment by reacting to the external environment.

Question 2

What does osmoregulation mean?

Answer 2

The process that regulates water content

Question 3

What happens when you’re too hot?

Answer 3

• you sweat (evaporates and carries away heat energy)
• Hairs lie flat (Prevent trapping of heat)
• Blood vessels dilate (allows blood to surface of skin, blood cause heat energy to be lost)

Question 4

What happens when you’re too cold?

Answer 4

• shiver (muscles contract to release heat)
• Hair stands on end (trapping a layer of air-heat energy)
• blood vessels constrict(less blood flows through to the skin meaning less heat it lost)

Question 5

What is the hypothalamus?

Answer 5

Part of the brain which detects a change in temperature and sends nerve impulses to the sweat glands

Question 6

What does negative feedback mean?

Answer 6

When your body reverses its change back to its original state

Question 7

What does vasoconstriction mean?

Answer 7

Blood vessels narrow, blood flow to the skin is reduced and heat loss is decreased.

Question 8

What does vasodilation mean?

Answer 8

Blood vessels widen, blood flow to skin is increases to skin and increases heat loss.

Question 9

What is CNS?

Answer 9

The central nervous system which consists of brain, nerves and the spinal chord.

Question 10

Stages in the reflex arc?

Answer 10

Recepter- sensory neurone- relay neurone- motor neurone- effector

Question 11

What are synapses?

Answer 11

Gap between the neurones

Question 12

What are neurotransmitters?

Answer 12

Chemical messages that carry info along the synapse

Question 13

How are stimuli and responses linked?

Answer 13

Stimulus- receptor - sensory neurone- cns- motor neurone - effector - response

Question 14

What do sensory neurones send impulses between?

Answer 14

from the sense organs to the cns

Question 15

What do motor neurones send impulses between?

Answer 15

from the cns to effector organs

Question 16

What is an axon?

Answer 16

fibres that carry electrical impulses from the cell body to the dendrites.

Question 17

What is an Dendron?

Answer 17

Fibre that carries electrical impulses to the cell body

Question 18

What cause involuntary and voluntary responses?

Answer 18

Involuntary responses are caused by the spinal chord

- voluntary responses are caused by the brain

Question 19

What is the myelin sheath?

Answer 19

A fatty substance surrounding dendrons and axons that speeds up the nerve impulses along the neurones.

Question 20

Where are hormones produced?

Answer 20

Produced and released by glands in the endocrine system. They are released into the bloodstream and have an affect on target organs

Question 21

What happens when your blood glucose is too high?

Answer 21

Insulin is release into the pancreas and converts glucose into glycogen which is stored in the liver.

Question 22

What happens when your blood glucose is too low?

Answer 22

Glucagen is released from the pancreas which helps convert glycogen into glucose which is released into the bloodstream.

Question 23

What is type 1 diabetes?

Answer 23

The pancreas does not produce enough insulin so to treat it people have daily injections of insulin.

Question 24

what is type 2 diabetes?

Answer 24

Pancreas produces insulin but the body becomes insensitive to it. Can be treated by careful eating, exercise and losing weight.

Question 25

4 main uses of plant hormones?

Answer 25

Selective weedkiller, fruit ripening, seedless fruit and rooting powder.

Question 26

What happens in selective weed killer?

Answer 26

Artificial auxin is used because it will only affect plants with broad leaves not narrow
farmers can kill weeds in crop fields

Question 27

What happens with rooting powder?

Answer 27

Plant cuttings are dipped in rooting powder making them grow and develop roots quickly.
large number of one plant can be done quickly

Question 28

How does seedless fruit work?

Answer 28

Fruit is sprayed and stops them from developing seeds.

some plants are naturally seedless so there sprayed with gibberelins to increase their size

Question 29

How does fruit ripening work?

Answer 29

Ethene gas is used to ripen fruit

farmers can control when to ripen their fruit and it can stop trees from dropping their fruit